In geometry class, the girl to boy ratio is $5$ to $2$. If there are $4$ boys, how many girls are there?
Answer: A ratio of $5$ girls to $2$ boys means that there is a group of $5$ girls for every group of $2$ boys. If there are $4$ boys, then there are $2$ groups of $2$ boys each. Because we know the ratio is $5:2$ , there must be $2$ groups of $5$ girls each. There is a total of $10$ girls in geometry class.